Due to the increasing cost, as well as the increasing scarcity, of many conventional metals used in the formation of high temperature structural components, increased emphasis has been placed on fiber reinforced composite articles which can take the place of their metal counterparts.
Techniques have been disclosed which describe fabrication processes for making fiber reinforced glass or glass-ceramic composites, four of which are commonly assigned U.S. Pat. Nos. 4,314,852; 4,412,854; 4,428,763; and 4,324,843, the disclosures of which are incorporated by reference herein.
Typically, such techniques incorporate the preparation of the matrix material into a slurry with an organic binder, drawing the reinforcing fibers through the slurry, coating the fibers, winding the coated fibers on a take-up reel, and drying the coated fibers forming a matrix impregnated tape. The matrix impregnated tape is then cut into desired lengths or shapes and laid up in proper fiber orientation, after which they are placed in an oven to burn off the binder. Then the lay-up is carefully placed in a mold and densified under heat and pressure forming the composite.
There are a number of disadvantages associated with this composite article manufacturing technique. One is that the removal of the organic binder which is used with the slurry matrix to improve the adhesion of the matrix to the fibers during the tape forming step, introduces an extra step which adds labor costs as well as energy costs to the process. In addition, such fugitive binders can be a source of unwanted impurities in the resultant composite. Another disadvantage is that the preparation of the slurry and its application onto the fibers, as well as the formation of the tape, is time-consuming and adds additional costs to the final article. Thirdly, the matrix is not always uniformly applied to the fibers, which may then create a nonuniform composite article. In addition, with the use of these processes, complex or three-dimensional composite structures are difficult to make.
Therefore, what is needed in this art is a method of manufacturing fiber reinforced composite articles which is less complex, less labor and energy intensive and allows for easier production of complex composite articles.